Laser Engraving using laser engravers
Edited from Wikipedia, the free encyclopedia

Laser engraving involves using lasers to engrave or mark an object. A computer is used to drive the movements of the laser head. Very precise and clean engravings can be achieved at a relatively high rate of speed. Laser engraving is applied to specially-designed "laserable" materials. These include polymer and metal alloys including stainless steel.

Laser engraving can also be use to "mark" material to prohibit the physical alteration of a surface in a subsequent process. Marking is a generic term that includes printing and hot-branding. In many instances, laser engraving machines are able to do marking that would have been done by other processes.

Laser Engraving Machines

A laser engraving machine consists of three main parts: a laser, a controller, and a surface. The laser is like a pencil - the beam emitted from it allows the controller to trace patterns onto the surface. The controller (usually a computer) controls the direction, intensity, speed of movement, and spread of the laser beam aimed at the surface. The surface is the material the laser can act on.

There are three main genres of engraving machines: The most common is the X-Y table where, usually, the workpiece (surface) is stationary and the laser moves around in X and Y directions drawing vectors. Sometimes the laser is stationary and the workpiece moves. Sometimes the workpiece moves in the Y axis and the laser in the X axis.

A second genre is for cylindrical workpieces (or flat workpieces mounted around a cylinder) where the laser effectively traverses a fine helix and on/off laser pulsing produces the desired image on a raster basis.

In the third method, both the laser and workpiece are stationary and galvo mirrors move the laser beam over the workpiece surface. Laser engravers using this technology can work in either raster or vector mode.

The Laser X-Y Table

For precise engravings, a laser table is used. A laser table (or "X-Y table") is a sophisticated setup of equipment used to guide the laser beam very precisely. The laser is usually fixed permanently to the side of the table and emits light towards a pair of movable mirrors so that every point of the table surface can be swept by the laser.

A typical setup of a laser table involves the fixed laser emitting light parallel to one axis of the table aimed at a mirror mounted on the end of an adjustable rail. The beam reflects off the mirror angled at 45 degrees so that the laser travels a path exactly along the length of the rail. This beam is then reflected by another mirror mounted to a movable trolley which directs the beam perpendicular to the original axis. In this scheme, two degrees of freedom (one vertical, and one horizontal) for etching can be represented.